Lignan-class compounds have been reported to have a variety of in vivo actions. For example, U.S. Pat. No. 4,427,694 discloses the effectiveness of sesamin in alleviating the symptoms of alcohol intoxication and/or alcohol or tobacco withdrawal; and JP 2-138120 A discloses the effectiveness of sesaminol and episesaminol in the treatment and prevention of allergosis such as bronchial asthma. The assignees of the subject application also confirmed various physiological actions of lignan-class compounds and, to date, they have revealed such effects as the blood cholesterol lowering action (Japanese Patent No. 3001589), the action of inhibiting Δ5-unsauration enzymes (Japanese Patent No. 3070611), the action of improving hepatic functions (Japanese Patent No. 3075358), cholesterol depression (Japanese Patent 3075360), the action of preventing sickness from drinking (Japanese Patent No. 3124062), the action of inhibiting the metabolism of cholesterol and bile acid, as well as lowering cholesterol (Japanese Patent No. 3283274), the carcinogenesis suppressing action (Japanese Patent No. 3183664), the breast cancer suppressing action (JP 05-043458 A), as well as the action of suppressing the generation of lipid peroxides (JP 05-051388 A), and the action of scavenging active oxygen (JP 06-227977 A).
Some of these effects of lignan-class compounds are preferably exhibited gradually over a prolonged period but there are also some effects that are desirably exhibited soon after they are ingested. For example, the effectiveness in preventing sickness from drinking and the effectiveness in scavenging active oxygen are desirably of quick action.
However, lignan-class compounds are hardly soluble in water and, what is more; they dissolve to only some extent in organic solvents that can be used in medicaments or foods. Such fat-soluble substances have the problem of not being easily absorbed in the living body. As a method of improving the bodily absorption of fat-soluble substances, it has been proposed to make finer micelles of fat-soluble substances (render them in finer particles). This exploits a nature of fat-soluble substances in that, the smaller the size of their particles, the more advantageous they are in terms of absorption by the digestive tract. To give a specific example, JP 2004-196781 A discloses a coenzyme Q10 containing water-soluble composition that comprises coenzyme Q10, a specified polyglycerin, fatty acid monoester, etc. and which is markedly improved in bodily absorption by adjusting the average particle size to 110 nm or smaller. As another example, JP 9-157159 A discloses a carotinoids containing composition comprising an oil phase that has carotinoids dissolved in oil or fat and that is emulsified in a water phase containing a polyglycerin fatty acid ester, lecithin and a polyhydric alcohol and which has the bodily absorption of a sparingly soluble substance, carotenoid, improved by adjusting the average particle size of the oil phase to 100 nm or smaller.
As described above, it is known to improve the absorbability (i.e., total amount of absorption) into the body of fat-soluble substances by making finer micelles of the substances (rendering them in finer particles). However, the above-mentioned documents do not either suggest or disclose anything about the rate at which the fat-soluble substances are absorbed into the body.    Patent Document 1: U.S. Pat. No. 4,427,694    Patent Document 2: JP 2-138120 A    Patent Document 3: Japanese Patent No. 3001589    Patent Document 4: Japanese Patent No. 3070611    Patent Document 5: Japanese Patent No. 3075358    Patent Document 6: Japanese Patent No. 3075360    Patent Document 7: Japanese Patent No. 3124062    Patent Document 8: Japanese Patent No. 3283274    Patent Document 9: Japanese Patent No. 3183664 (JP 04-159221 A)    Patent Document 10: JP 05-043458 A    Patent Document 11: JP 05-051388 A    Patent Document 12: JP 06-227977 A    Patent Document 13: JP 2004-196781 A    Patent Document 14: JP 9-157159 A